The comments came in a rare press conference Tuesday by the highly secretive Public Security Ministry, which has nationwide responsibility for law and order in China. The ministry spokesman gave a favorable report on the results of the government's 15-month crackdown on crime, although he presented little new information and avoided providing statistics on the number of criminal executions and political prisoners in the country.

Mr. Wang defended the government's anticrime campaign, which has included a large number of executions: ''It is not true that we have emphasized capital punishment in the past year. It was true that we executed some people . . . but it was only because in the previous few years we didn't do a good job punishing the criminal offenders. . . . In a big country like ours with a population of 1 billion, it is good to have some criminals executed so as to educate others.''

The Chinese government launched a severe crackdown on crime in August 1983. In the months immediately afterward, tens of thousands of people were arrested and thousands were executed. Many of the executions took place following rallies in which the criminals were paraded before the public.

No official data has been made available on the exact number of arrests and executions. But by January of this year, foreign observers in China estimated the number of executions to be between 5,000 and 10,000. The number of arrests and executions have diminished in the past six months, judging from public posters which list names of criminals, their offenses, and the sentences received.

Mr. Wang appeared to repeat figures cited in an interview with Public Security Minister Liu Fuzhi last summer. The national crime rate is now five cases per 10,000 people, Mr. Wang said - down from eight cases per 10,000 prior to the anticrime campaign. Even before August 1983, China had one of the lowest crime rates in the world. (The National Institute of Justice estimates that the United States crime rate in 1983 was 516 per 10,000.)

In the past year, about 120,000 lawbreakers surrendered, Wang said. Some 70, 000 cases were prosecuted following public tips on suspected offenses.

There has been a sharp rise in economic crimes in recent years, and 70 percent of the criminal cases in the past year involved larceny, Wang said. Many economic crimes now bring the death penalty under amendments to China's criminal code.

Many of those arrested and executed in the past 15 months are people in their 30s, often unemployed. Wang said crime among youth was caused by the residual influences of the anarchy of the Cultural Revolution (1966-76) and the negative influences from outside the country.

He said that China had no political prisoners, but conceded there are people detained for ''counterrevolutionary'' offenses. There are no reliable estimates of the total number of such prisoners in China, but the number almost certainly runs into the thousands.

Counterrevolutionary offenses include espionage and treason as well as counterrevolutionary agitation, organizing and taking part in counterrevolutionary groups, and inciting to resist arrest or to violate state laws. Amnesty International, the London-based human rights organization, says people exercising basic human rights have most often been charged with these latter offenses.